
class UnitOfWOrk
{
      private :
             static UnitOfWork instance;
             UnitOfWork();
             GenericRepository<User> userRepository;
             GenericRepository<Customer> customerRepository;
             GenericRepository<Book> bookRepository;
           
      public :
             static void getInstance();
             GenericRepository<User> getUserRepository();
             GenericRepository<Customer> getCustomerRepository();
             GenericRepository<Book> getBookRepository();
};
